1. Field of the Invention
The present invention relates to a photosensor and, more particularly, to a photosensor suitable for use in color facsimile equipment, an optical character recognition device, a color decomposing device and the like.
2. Description of the Prior Art
FIG. 1 shows schematically a photosensor of a conventional color facsimile transmitter, including a manuscript drum 1, light source lamps 2, a lens 3, a slit 4 and dichroic mirrors 5. The transmitter also includes a red filter 6, a green filter 7 and a blue filter 8 with a photomultiplier being indicated by reference numeral 9. The light emitted from the light source lamp 2 is reflected by the manuscript which is wound around the drum 1, and is focussed by the lens 3. The light then passes through the slit 4, and is decomposed into three elementary colors of red, green and blue, by means of two dichroic mirrors 5 and three color filters 6, 7 and 8. These are converted into electric signals by the photomultiplier 9, and are read electrically. The scanning is effected by mechanically rotating the manuscript drum 1, while continuously mechanically shifting the optical system 2-9.
The requirements for a color facsimile transmitter include reduced size and weight, as well as a shortened reading time. However, the scanning system in the conventional transmitter relying upon the mechanical shift of the optical lens system poses the following disadvantages.
1. The use of the optical lens system makes it difficult to reduce the size of the transmitter.
2. The mechanical shifting of the optical lens system is not preferred from the view point of reduction of the size of the transmitter. Also, the weight of the transmitter is increased by the shifting mechanism.
3. The mechanical scanning requires an impractically long reading time.
A novel photosensor has been proposed by at least one of the co-inventors of this application, and has been filed as copending U.S. patent application Ser. Nos. 903,161 and 918,273, filed May 5, 1978 and June 22, 1978, respectively. This photosensor has a sheet-like bundle of optical fibers which extends across the thickness of a base member from a first to a second surface thereof. Rows of photosensitive elements are integrally provided with the base member and are disposed on one surface of the sheet-like optical fibers, while the other surface constitutes a surface for reading the information. This photosensor, however, cannot read color information.
It is therefore an object of the present invention to overcome the above described disadvantages of the prior art arrangements, by providing a photosensor which enables the reading of color information in a shorter reading time, without making use of an optical lens system, and which is suitable for use in a color facsimile transmitter, a character recognition device, a color decomposing device and the like, and which enables these devices to have reduced sizes.